Nx OsOperating system · Cisco
CVE-2020-3168
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA vulnerability in the Secure Login Enhancements capability of Cisco Nexus 1000V Switch for VMware vSphere could allow an unauthenticated, remote attacker to cause an affected Nexus 1000V Virtual Supervisor Module (VSM) to become inaccessible to users through the CLI. The vulnerability is due to improper resource allocation during failed CLI login attempts when login parameters that are part of the Secure Login Enhancements capability are configured on an affected device. An attacker could exploit this vulnerability by performing a high amount of login attempts against the affected device. A successful exploit could cause the affected device to become inaccessible to other users, resulting in a denial of service (DoS) condition requiring a manual power cycle of the VSM to recover.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceA vulnerability in the Secure Login Enhancements of Cisco Nexus 1000V Virtual Supervisor Module (VSM) allows an unauthenticated remote attacker to cause denial of service by performing excessive failed CLI login attempts. The improper resource allocation during these failed attempts exhausts resources, rendering the VSM inaccessible and requiring manual power cycle to recover.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Nx OsOperating system
= 5.2\(1\)sv3\(4.1a\)CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the device and installed NX-OS versionRun 'show version' or access VSM management interface to confirm device type is Cisco Nexus 1000V Virtual Supervisor Module and record the installed NX-OS versionAffected if The installed version is 5.2(1)sv3(4.1a)
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Verify the exact software version stringConfirm the full version string matches exactly 5.2(1)sv3(4.1a) as listed in the affected versionsAffected if The version string is exactly 5.2(1)sv3(4.1a)
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Check if Secure Login Enhancements is enabledAccess VSM CLI and run 'show running-config | include secure-login' or similar command to display the Secure Login Enhancements configurationAffected if Secure Login Enhancements feature is enabled in the current configuration
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Assess management interface accessibilityReview network access controls, ACLs, or management VLAN configuration to determine if the VSM management interface (typically mgmt0) is reachable from untrusted networksAffected if Management interface is accessible from networks where unauthenticated attackers can reach the device
The environment is affected if running Nexus 1000V VSM with NX-OS version 5.2(1)sv3(4.1a) AND Secure Login Enhancements is enabled AND the management interface is accessible to potential attackers.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply the Cisco patch when available. If the feature is not required, disable Secure Login Enhancements. Restrict management interface access via ACLs or network segmentation to limit exposure to unauthenticated login attempts.
Fix this in Nx Os
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,168.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-3168 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-3168 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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